Volcanic hazard

[6] Cinders are flaming pieces of ejected volcanic material which could set fire to homes and wooded areas.

[7] A pyroclastic flow is a fast-moving (up to 700 km/h) extremely hot (~1000 °C) mass of air and tephra that charges down the sides of a volcano during an explosive eruption.

[8][9][10] When pyroclastic materials mix with water from a nearby stream or river, they can turn the watercourse into a fast moving mudflows.

The latter are referred to as secondary lahars and form when rain wets the ash and debris already on a landscape and stick together, rolling along the topography.

[15] Large, explosive volcanic eruptions inject water vapor (H2O), carbon dioxide (CO2), sulfur dioxide (SO2), hydrogen chloride (HCl), hydrogen fluoride (HF) and ash (pulverized rock and pumice) into the stratosphere to heights of 16–32 kilometres (9.9–19.9 mi) above the Earth's surface.

As the aerosols grow and coagulate, they settle down into the upper troposphere where they serve as nuclei for cirrus clouds and further modify the Earth's radiation balance.

Large injections may cause visual effects such as unusually colorful sunsets and affect global climate mainly by cooling it.

[20] Long period earthquakes, which happen when magma is suddenly forced into the surrounding rocks, are generally seen as a precursor to the actual eruption.

[20] A volcanic winter is thought to have taken place around 70,000 years ago after the supereruption of Lake Toba on Sumatra island in Indonesia.

[23] It has been suggested volcanic activity caused or contributed to the End-Ordovician, Permian-Triassic, Late Devonian mass extinctions, and possibly others.

[25] The 1815 eruption of Mount Tambora created global climate anomalies that became known as the "Year Without a Summer" because of the effect on North American and European weather.

[26] Agricultural crops failed and livestock died in much of the Northern Hemisphere, resulting in one of the worst famines of the 19th century.

[27] The freezing winter of 1740–41, which led to widespread famine in northern Europe, may also owe its origins to a volcanic eruption.

[28] According to John Ewert and Ed Miller in a 1995 publication, "a great majority of the world's potentially active volcanoes are unmonitored".

[29] By monitoring the seismic and geological activity, the USGS can warn people ahead of time about impending danger.

Miniaturizing said systems offers the possibility to increase the measurement frequency by reducing weight and cost and therefore improve monitoring.

Commonly measured gases are CO2 and SO2 which allow to detect upcoming changes in volcanic activity, as it was already shown at e.g. Etna, Italy.